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Breakthrough: Harvard scientists link autism to key neurotransmitter

A team of Harvard researchers have made a huge breakthrough in the study of autism, linking the condition to a specific neurotransmitter in the brain.

A team of neuroscientists from Harvard and MIT has made a huge breakthrough in the study of autism. According to a report from the Huffington Post, the researchers have established a link between a neurotransmitter, GABA, and various symptoms of autism. The discovery may lead to a deeper understanding of the condition and pave the trail for new methods of treating and identifying it.

According to MIT McGovern Institute for Brain Research postdoc Caroline Robertson, “This is the first connection in humans between a neurotransmitter in the brain and an autistic behavioral symptom.”

GABA inhibits brain cells from firing in response to stimuli from the outside environment. Robertson described its role as curbing the feeling of “runway excitation” the brain experiences.

Researchers have long suspected that a deficiency in the GABA neurotransmitter can lead to heightened sensitivity to sensory stimulus, a result of overexcited neurons in the brain. Robertson explains that GABA helps filter out irrelevant signals from the outside world, allowing people to focus on a task at hand.

Children with autism are often easily distracted by physical sensations like an itchy shirt, or by background noises like the humming of an air system. They are often overwhelmed by loud noises and highly stimulating situations. Understanding this hypersensitivity and what the brain does to address it could lead to further insights into how autism can be diagnosed and treated.

Robertson and the team of scientists asked a group of participants, 50 percent of who had autism, to carry out a visual task that required them to tune out extra information. Successfully completing the task depended on the participant’s ability to focus on visual inputs alternating between the left and right eyes.

They found that the adults with autism switched back and forth between stimuli only half as much as the control group. They were noticeably hindered in suppressing one image so they could turn their focus to the other.

Following the task, the researchers measured the levels of GABA activity in the participants’ brains. They found that the participants who had an easier time suppressing the non-relevant image in the exercise had higher levels of GABA in the brain, suggesting that the neurotransmitter played a key role in allowing them to tune out unnecessary information and focus on the task they were given.

The study doesn’t definitively name GABA deficiency as the cause for autism, and further research will need to be carried out in order to fully understand the link.

A press release from Harvard University describing the details of the study can be found here.